System and method of monitoring an environmental parameter along a predetermined route

ABSTRACT

A monitoring system has a vehicle and a monitoring device. The vehicle is movable along a predetermined route, and the monitoring device is detachably mounted to the vehicle. The vehicle has a photonic device configured to read position information according to detection of a positioning tag positioned at a predetermined position along the predetermined route. The monitoring device has a sensor configured to monitor an environmental parameter and a controller communicatively coupled to the sensor and the photonic device. The controller is configured to record the monitored environmental parameter along the predetermined route and the position information.

TECHNICAL FIELD

The present disclosure relates to semiconductor manufacturing, and more particularly, to a system and method of monitoring an environmental parameter along a predetermined route.

BACKGROUND

During manufacturing of semiconductor integrated circuits (ICs), semiconductor wafers are subjected to multiple processing steps at different processing equipments. For example, to complete the fabrication of an IC chip, various steps of deposition, cleaning, ion implantation, etching, and/or passivation steps are generally carried out in different processing equipments. Therefore, fabrication facilities generally include transportation systems such as an automated material handling system (AMHS) for transporting the semiconductor wafers among the processing equipments.

Further, in a fabrication facility, a carefully controlled environment when transporting the semiconductor wafers is important due to the delicate nature of the chips. Abnormalities in vibration, temperature, humidity, or level of contamination along the route of transportation increase the risk of unexpected particles or features formed on the wafers and decrease the yield rate of the manufacturing process. Therefore, there is a need for monitoring one or more environmental parameters when transporting the semiconductor wafers.

DESCRIPTION OF THE DRAWINGS

One or more embodiments are illustrated by way of example, and not by limitation, in the figures of the accompanying drawings, wherein elements having the same reference numeral designations represent like elements throughout and wherein:

FIG. 1A is a perspective view of a portion of a monitoring system according to an embodiment;

FIG. 1B is a cross-sectional view of the monitoring system depicted in FIG. 1A;

FIG. 2 is a diagram of exemplary predetermined routes and positioning tags according to an embodiment;

FIG. 3 is a system diagram of the monitoring system for monitoring an environmental parameter along a predetermined route according to an embodiment;

FIG. 4 is a flow chart of a process for monitoring an environmental parameter according to an embodiment;

FIG. 5A is a chart of a recorded environmental parameter according to an embodiment;

FIG. 5B is a chart of the recorded environmental parameter and overlaid recorded position information according to an embodiment; and

FIG. 6 is a diagram of an exemplary visualized presentation of predetermined routes with dots depicted to identify positions of abnormality.

DETAILED DESCRIPTION

FIG. 1A depicts a portion of a monitoring system 100 for monitoring an environmental parameter along a predetermined route according to an embodiment. A track 102 is positioned to define the predetermined route along which the monitoring system 100 is movable. The monitoring system 100 comprises a vehicle 110 configured to move along track 102 and a monitoring device 120 detachably mounted to vehicle 110 and configured to monitor an environmental parameter. In some embodiments, the monitoring system 100 is an AMHS adapted to perform the monitoring function. In some embodiments, the monitoring system 100 monitors one or more environmental parameters including vibration, temperature, humidity, or level of contamination along the route of transportation, or any combination thereof.

FIG. 1B is a cross-sectional view as seen if looking at (imaginary) plane A of the monitoring system 100 depicted in FIG. 1A. In at least one embodiment, track 102 is a guide rail mounted to a ceiling 104 in a fabrication facility, and vehicle 110 is movably mounted to the guide rail. In some other embodiments, track 102 comprises a rail, a magnetic strip, a conveyor, or a combination thereof. Depending on the type of track and vehicle, in some embodiments, the track is mounted on a floor or an elevated structure. Vehicle 110 is configured to carry a payload and move along the track. The payload, in some exemplary applications, comprises a Front Opening Unified Pod (FOUP) designed to hold one or more semiconductor wafers. In at least one embodiment, the payload is monitoring device 120.

Further, a positioning tag 122 is positioned at a predetermined position along the predetermined route and vehicle 110 comprises a photonic device 124 configured to read position information from positioning tag 122 according to detection of positioning tag 122. In some embodiment, positioning tag 122 is positioned on or adjacent to the track 102. In at least one embodiment, positioning tag 122 comprises a barcode and the photonic device 124 is a barcode reader for detecting the barcode on the positioning tag 122. In some other embodiments, positioning tag 122 comprises an optical feature such as a barcode, a text, a figure, or a combination thereof and photonic device 124 is configured to be responsive to all or a portion of visible lights, infrared lights, or ultraviolet lights, or any combination thereof, that it received either directly from a light source or by reflection.

FIG. 2 depicts an exemplary layout of predetermined routes and positioning tags according to an embodiment. A plurality of positioning tags 202 a through 202 i similar to the positioning tag 122 (FIG. 1B) are positioned at a plurality of predetermined positions along the routes or tracks 212 a through 212 f. In some embodiments, the position information acquired by the vehicle 110 is sent to a traffic control center for controlling the traffic on the tracks, i.e., the movement of at least one vehicle 110 on the tracks. For example, at a specific time in at least one embodiment, there is more than one vehicle 110 mounted on and mobile along the tracks 212 a-212 f in order to transport semiconductor wafers to different processing equipment in the fabrication facility. The traffic control center directs vehicles to a corresponding destination processing equipment while avoiding collisions between the vehicles. Further, in order to monitor an environmental parameter in the fabrication facility along the tracks 212 a-212 f, at least one vehicle 110 carries a monitoring device 120 instead of one or more FOUPs holding semiconductor wafers or other payload types. In some embodiments, the vehicle 110 with the monitoring device 120 moves along a predetermined route for monitoring the environmental parameter along the predetermined route.

In some embodiments, on top of the positioning tags 202 a-202 i necessary for traffic control, more positioning tags are placed along the tracks 212 a-212 f at sections where higher spatial resolution for monitoring the environmental parameter is preferred. For example, in an embodiment in which the vibration of the vehicle 110 along the tracks 212 a-212 f is monitored, more positioning tags are positioned at positions where track assemblies are jointed, where there is a track junction, or where there is a curved track.

FIG. 3 depicts a system diagram of a monitoring system 300 for monitoring an environmental parameter along a predetermined route according to an embodiment. Similar to the monitoring system 100 (FIGS. 1A and 1B), the monitoring system 300 comprises a vehicle 310 configured to move along the predetermined route and a monitoring device 330 detachably mounted to the vehicle 310. In addition, in at least one embodiment, the monitoring system 300 further comprises a log server 350 configured to receive the recorded monitored environmental parameter and the recorded position information from the monitoring device 330. The log server 350 comprises a display device 352 configured to display a visualized presentation of the predetermined route, the recorded monitored environmental parameter, and/or the recorded position information. In some embodiments, the log server 350 further comprises a microcontroller 354 electrically coupled to the display device 352 to control the operation of the display device 352 and a storage 356 electrically coupled to the microcontroller 354 to store the recorded monitored environmental parameter received from the monitoring device 330.

The vehicle 310 is configured to transport the monitoring device 330 and move along the predetermined route, such as a track 102 (FIG. 1B). In some embodiments, vehicle 310 comprises a photonic device 312, a controller 314 communicatively coupled to the photonic device 312, and a communication module 316 communicatively coupled to the photonic device 312 and the controller 314. The photonic device 312 reads position information according to detection of a positioning tag positioned at a predetermined position along the route or track. The communication module 316 transmits the position information to the monitoring device 330.

In at least one embodiment, the controller 314 manages the operation of the photonic device 312 and the communication module 316. Further, in some embodiments, the controller 314 also controls a motor of the vehicle 310 in order to drive the vehicle 310 along the route or track based on a predetermined traffic control functionality programmed in a storage device of the vehicle 310 or instructions issued by a traffic control center to the vehicle 310.

In at least one embodiment, the monitoring device 330 comprises a sensor 332, a controller 334, a storage device 338, and a display 340. The controller 334 is communicatively coupled to the sensor 332, the storage device 338, and the display 340 to manage the operation of the monitoring device 330. In some embodiments, the controller 334 comprises a general-purpose microcontroller, a processor, or an application-specific integrated circuit (ASIC) and the storage device 338 comprises a hard drive, a flash drive, a DRAM, an SRAM, or an applicable storage device such as a computer readable medium storing instructions for execution by the controller 334.

The sensor 332 monitors the environmental parameter. In at least one embodiment, the sensor 332 is a vibration sensor for monitoring a vibration along the route or track of the vehicle 310 to which the monitoring device 330 is attached. For example, in some embodiments, the sensor 332 is a tri-axial vibration sensing device. The tri-axial vibration sensing device continuously, or repetitively according to a preset timing pattern, monitors vibrations and decomposes them into x-axis, y-axis, and z-axis components. In some embodiments, the sensor 332 is a vibration sensing device capable of recording vibrations according to less or more than three axes. In some other embodiments, the sensor 332 is configured to detect vibration, temperature, humidity, contamination levels in the air, noise, bio-hazardous particles, or any combination thereof. In at least one embodiment, the sensor 332 is a camera configured to acquire still images or video clips.

In some embodiments, the controller 334 records the monitored environmental parameter and stores the parameter in the storage device 338. For example, the controller 334 receives the vibration information from the sensor 332 and records the vibration information in a time-based manner with a plurality of time tags along a time axis. In some embodiments, each stored vibration data point is associated with a time tag. Further, in some embodiments, the controller 334 is communicatively coupled with the photonic device 312 through communication module 336. In some embodiments, the controller 334 receives the position information from the vehicle 310 and stores the position information in the storage device 338. In at least one embodiment, while recording the monitored environmental parameter and the position information, the controller 334 also associates the position information with at least one of the plurality of time tags.

The communication module 336 of monitoring device 330 communicates with the communication module 316 of vehicle 310. In some embodiments, communication modules 316 and 336 are coupled in a wired manner. For example, when mounting the monitoring device 330 onto the vehicle 310, as depicted in FIG. 1B, the communication modules 316 and 336 are electrically coupled through a USB connection, an IEEE-1394 connection, a RS-232 connection, an optical fiber, or another applicable connection, either serial or parallel. In some embodiments, communication module 316 is electrically connected to a set of connecting pins, and communication module 336 is electrically connected to a set of connecting pads, where the connecting pins and corresponding connecting pads form electrical contacts with each other when the monitoring device 330 is mounted onto the vehicle 310.

In yet some other embodiments, the communication modules 316 and 336 are communicatively coupled in a wireless manner. For example, in at least one embodiment, the communication module 316 and the communication module 336 are BLUETOOTH communication modules capable of communicating with each other according to a BLUETOOTH communication protocol. In some embodiments, the communication module 316 and the communication module 336 are wireless LAN modules, infrared communication modules, laser transceivers, or any applicable wireless communication modules according to industry protocols or proprietary protocols.

In some embodiments, a log server 350 comprising a display device 352 configured to communicate with the monitoring device 330 in order to receive the recorded monitored environmental parameter and the recorded position information. In at least one embodiment, the monitoring device 330 is removed from the vehicle 310 after being transported along a predetermined route by the vehicle 310, and then the log server 350 is communicatively coupled to the monitoring device 330 in a wired or wireless manner, such as the exemplary communication methods presented above for communication modules 316 and 336. In at least another embodiment, the log server 350 is communicatively coupled to the monitoring device 330 in a wireless manner and receives the recorded monitored environmental parameter and position information while the monitoring device 330 remains mounted to and transported by the vehicle 310.

The display device 352 displays the visualized presentation of the monitoring results received from the monitoring device 330. In some embodiments, the display device 352 is an LCD monitor. Further, in at least one embodiment, the monitoring device 330 also comprises a display device 340 for showing the operational status of the monitoring device 330 and/or the readings of the monitored environmental parameter. In some embodiments, the display device 340 also displays the visualized presentation of the monitoring results of the monitoring device 330. In at least some embodiments, the display device 340 is an LCD monitor or an LED array.

FIG. 4 is a flow chart of a process for monitoring an environmental parameter according to an embodiment. The flow chart is merely exemplary, and additional functions may be performed before, after, or in between the exemplary steps. Further, in some embodiments, the exemplary functionality is performed in a different order.

In step 402, a vehicle 310 carrying a monitoring device 330 is driven along a predetermined route for monitoring an environmental parameter. In Step 404, position information is read from a positioning tag by a photonic device 312 according to detection and/or scanning of the positioning tag positioned at a predetermined position along the predetermined route. In step 406, the environmental parameter is monitored by a monitoring device 330 detachably mounted to the vehicle. In some embodiments, the monitoring device 330 is configured to detect vibration, temperature, humidity, contamination levels in the air, noise, bio-hazardous particles, or any combination thereof. In at least one embodiment, the monitoring device 330 is configured to acquire still images or video clips.

In step 408, the monitored environmental parameter and the position information are recorded by the monitoring device 330 along the predetermined route. In some embodiments, monitoring device 330 records the vibration in a time-based manner with a plurality of time tags and associates the position information with at least one of the plurality of time tags.

In step 410, a display device 340 or 352 displays a visualized presentation of the predetermined route, the recorded monitored environmental parameter, and/or the recorded position information is shown by.

FIG. 5A is a chart of a recorded environmental parameter versus a time axis according to an embodiment. In some embodiments, when the monitoring device 330 starts to record the monitored environmental parameter, the monitored results are recorded in a time-based manner. In at least some embodiments, each monitored result is associated with a time tag generated by the monitoring device 330. For example, in at least one embodiment, a vibration of the vehicle 330 is monitored by the monitoring device 330. The monitoring device 330 continuously monitors the vibration and associates the results with time tags. Therefore, the relation between recorded monitored vibration versus a time axis is depicted in FIG. 5A. However, in some applications, because more than one vehicle may move along the tracks or routes at the same time, the vehicle 310 carrying the monitoring device 330 is ordered by the traffic control center to stop, speed up, or slow down from time to time. That is, the vehicle 310 does not necessarily travel at a constant speed. Thus, merely from the information depicted in FIG. 5A, the spatial relationship between the recorded monitored environmental parameter and its corresponding positions along the predetermined route cannot be properly determined.

FIG. 5B is a chart of a recorded environmental parameter versus a time axis in combination with recorded position information associated with a plurality of time tags according to an embodiment. In some embodiments, the monitoring device 330 also receives position information from the vehicle and associates the received position information with time tags. In some embodiments, the read position information is translated into a text code for recording. As such, the spatial relationship between the recorded monitored environmental parameter and the corresponding positions along the predetermined route are determinable from the recorded monitored environmental parameter and the position information (such as the Position Tags #1-#4 depicted in FIG. 5B).

FIG. 6 is a diagram of an exemplary visualized presentation of predetermined routes with dots depicted to identify positions of abnormality. In order to better identify the positions along the predetermined route where abnormality is suggested by the monitored environmental parameter and thus further actions may be necessary, the display device 610 displays a visualization of the recorded monitored environmental parameter. In at least one embodiment, the display of visualized presentation of the monitoring results is performed by the log server 350 executing a program or a set of instructions stored in a storage device 356 of the log server 350.

In some embodiments, a layout of the predetermined route as well as other possible routes, such as tracks 612 a-612 g, is depicted on the display device 610. At least one data point in the recorded monitored environmental parameter that will be identified in the visualized presentation is selected. For example, if the monitored environmental parameter is vibration of monitoring device 330 while mounted to the vehicle 310, a data point in the recorded monitored environmental parameter having a vibration value greater than a predetermined threshold (such as 0.5G for example) can be selected as a selected data point associated with a location of an abnormal occurrence.

Further, a position on the layout of the predetermined route can be selected according to the recorded position information and the selected data point. Numerical calculations, such as an interpolation or an extrapolation to determine a position corresponding to the selected data point, are performed in order to more accurately determine the position. Then, the position corresponding to the location of abnormal occurrence is identified on the layout of the predetermined route displayed on the display device 610. Based on the visualized presentation, further acts can be taken to cure the identified abnormality. For example, if the vibration at a specific position along a track exceeds the predetermined threshold, a nearby track assembly, track joint or track junction is examined, adjusted, or replaced, to ease the vibration.

In some embodiments, the recorded monitored environmental parameter is screened by two or more threshold values. For example, when monitoring the vibration of the vehicle along the predetermined route, a first group of data points having values greater than 0.5G and a second group of data points having values greater than 0.4G, but no greater than 0.5G, are selected. Subsequently, the positions on the depicted layout of the tracks 612 a-612 g are determined, and these positions are identified on the display device 610 with predetermined symbols 616 a-616 d and 618 a-618 b. In at least one embodiment, positions corresponding to the first group of data points are depicted with red dots such as dots 616 a-616 d, and positions corresponding to the second group of data points are depicted with yellow dots such as dots 618 a-618 b. In some embodiments, instead of colored dots, the positions corresponding to the first and second groups of data points are depicted by dots with shading or patterns, colored segments, or arrows pointing to corresponding positions on the layout of tracks 612 a-612 g.

It will be readily seen by one of ordinary skill in the art that the disclosed embodiments fulfill one or more of the advantages set forth above. After reading the foregoing specification, one of ordinary skill will be able to affect various changes, substitutions of equivalents and various other embodiments as broadly disclosed herein. It is therefore intended that the protection granted hereon be limited only by the definition contained in the appended claims and equivalents thereof. 

What is claimed is:
 1. A monitoring system for a wafer handling system comprising: a vehicle movable along a predetermined route, the vehicle comprising: a photonic device configured to read position information according to detection of a positioning tag positioned at a predetermined position along the predetermined route; and a monitoring device detachably mounted to the vehicle, the monitoring device comprising: a sensor configured to monitor an environmental parameter; and a controller communicatively coupled to the sensor and the photonic device, the controller being configured to: record the monitored environmental parameter along the predetermined route as data points, each data point associated with a time tag in a plurality of time tags; and record the position information and associate the position information with corresponding one or more of the plurality of time tags, wherein the number of time tags associated with position information is less than the number of time tags associated with the monitored environmental parameter.
 2. The monitoring system of claim 1, wherein the environmental parameter is vibration of the monitoring device when mounted to the vehicle, and the sensor is a vibration sensor.
 3. The monitoring system of claim 2, wherein the vibration sensor is a tri-axial vibration sensing device.
 4. The monitoring system of claim 1, wherein the positioning tag comprises an optical feature.
 5. The monitoring system of claim 4, wherein the optical feature is a barcode, a text, a figure, or a combination thereof.
 6. The monitoring system of claim 1, further comprising: a display device configured to show a visualized presentation of the predetermined route, the recorded monitored environmental parameter, and the recorded position information.
 7. The monitoring system of claim 6, wherein the display device is further configured to show at least one abnormal occurrence identifier.
 8. The monitoring system of claim 1, wherein the vehicle further comprises a first communication module communicatively coupled to the photonic device, and the monitoring device further comprises a second communication module communicatively coupled to the controller and is configured to communicate with the first communication module.
 9. The monitoring system of claim 8, wherein the first communication module and the second communication module are wireless communication modules.
 10. The monitoring system of claim 1, further comprising: a server configured to receive the recorded monitored environmental parameter and the recorded position information from the monitoring device.
 11. A method of monitoring an environmental parameter, comprising: driving a vehicle along a predetermined route; reading, by a photonic device, position information according to detection of a positioning tag positioned at a predetermined position along the predetermined route; monitoring an environmental parameter by a monitoring device detachably mounted to the vehicle; and recording, by the monitoring device, the monitored environmental parameter along the predetermined route and the position information, wherein the recording the monitored environmental parameter and the position information comprises: recording the monitored environmental parameter as data points, each data point associated with a time tag in a plurality of time tags; and associating the position information with corresponding one or more of the plurality of time tags, wherein the number of time tags associated with position information is less than the number of time tags associated with the monitored environmental parameter.
 12. The method of claim 11, wherein the reading position information comprises translating an optical feature on the positioning tag into a text code.
 13. The method of claim 11, wherein the environmental parameter is vibration of the monitoring device when being mounted to the vehicle.
 14. The method of claim 11, further comprising: displaying, by a display device, a visualized presentation of the predetermined route, the recorded monitored environmental parameter, and the recorded position information.
 15. The method of claim 14, wherein the showing a visualized presentation comprises: depicting a layout of the predetermined route on the display device; selecting at least one data point in the recorded monitored environmental parameter that will be identified in the visualized presentation; selecting a position on the layout of the predetermined route according to the recorded position information and the selected at least one data point; and identifying the position on the layout of the predetermined route on the display device.
 16. The method of claim 15, wherein the identifying the position on the layout of the predetermined route comprises: depicting a colored dot corresponds to the selected position on the layout of the predetermined route on the display device.
 17. The method of claim 15, wherein the environmental parameter is vibration of monitoring device when being mounted to the vehicle, and the selected at least one data point has a vibration value greater than a predetermined threshold.
 18. The method of claim 14, wherein the visualized presentation comprises at least one abnormal occurrence identifier.
 19. An Automated Material Handling System (AMHS) comprising: a track; a positioning tag positioned at a predetermined position along the track; a monitoring device; and a vehicle configured to carry the monitoring device and move along the track, the vehicle comprising: a photonic device configured to read position information according to detection of the positioning tag; and a communication module communicatively coupled to the photonic device and configured to transmit the position information to the monitoring device, wherein the monitoring device comprises: a controller communicatively coupled to the communication module of the vehicle, the controller being configured to record the position information and generate a visualized presentation of the track and at least one abnormal occurrence identifier associated with the recorded position information.
 20. The AMHS of claim 19, wherein the positioning tag comprises an optical feature. 